<!DOCTYPE html>
<html lang="zh-cn">
    <head>
        <meta charset="UTF-8"/>
        <meta name="viewport" content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0" />
        <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
        <title>Document</title>
        <style>
        body,p{margin: 0;}
        h2{margin: 0;font-size:100%;}
        ul{margin: 0;padding: 0;list-style: none;}   
        a{text-decoration: none;color:inherit;}
        .box{width: 572px;border: 1px solid #999;overflow: hidden;}
        .nav{margin-left: -1px;font: 14px "微软雅黑";overflow: hidden;background-color: #f1f1f1;}
        .navI{float: left;width: 33.333%;box-sizing: border-box;position:relative;}
        .navI-tit{position:absolute;top:0;left:0;right:0;box-sizing: border-box;line-height: 40px;height: 40px;text-align: center;cursor: pointer;border-left: 1px solid #cecece;border-bottom: 1px solid #cecece;}
        .navI-txt{width: 572px;height:200px;margin-top: 40px;text-indent:2em;line-height: 2;background:#fff;}
        .ml1{margin-left: -100%;}
        .ml2{margin-left: -200%;}
        .navI_active{z-index:1;}
        /*重点代码*/
        .navI-txt:target{position:relative;z-index:1;}
        .navI-txt:target ~ .navI-tit{background:#fff;border-bottom:none;}
        </style>
    </head>
    <body>
        <div class="box">
            <ul class="nav">
                <li class="navI navI_active">
                    <p class="navI-txt" id="kc">课程内容</p>
                    <a class="navI-tit" href="#kc">课程</a>
                </li>
                <li class="navI">
                    <p class="navI-txt ml1" id="xx">学习计划内容</p>
                    <a class="navI-tit" href="#xx">学习计划</a>
                </li>
                <li class="navI">
                    <p class="navI-txt ml2" id="jn">技能图谱内容</p>
                    <a class="navI-tit" href="#jn">技能图谱</a>
                </li>
            </ul>   
        </div>
    </body>
</html>